package org.liuyuantao.thread.concurrent;

import java.util.concurrent.CyclicBarrier;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * 允许一组线程互相等待,直到到达某个公共屏障点,才会进行后续任务
 * 线程间等待,所有线程都完成后再继续执行
 * 类似于出去旅游,一批人集合,所有的人都集合了才去下一个景点自由活动,到时间再进行集合,再到下一个景点
 */
public class CyclicBarrierTest {

    public static void main(String[] args) {
        ExecutorService service = Executors.newCachedThreadPool();
        final CyclicBarrier cb = new CyclicBarrier(3);
        for (int i = 0; i < 3; i++) {
            Runnable runnable = () -> {
                try {
                    Thread.sleep((long) (Math.random() * 10000));
                    System.out.println("线程" + Thread.currentThread().getName() +
                            "即将到达集合地点1，当前已有" + (cb.getNumberWaiting() + 1) + "个已经到达，" + (cb.getNumberWaiting() == 2 ? "都到齐了，继续走啊" : "正在等候"));
                    cb.await();
                    Thread.sleep((long) (Math.random() * 10000));
                    System.out.println("线程" + Thread.currentThread().getName() +
                            "即将到达集合地点2，当前已有" + (cb.getNumberWaiting() + 1) + "个已经到达，" + (cb.getNumberWaiting() == 2 ? "都到齐了，继续走啊" : "正在等候"));
                    cb.await();
                    Thread.sleep((long) (Math.random() * 10000));
                    System.out.println("线程" + Thread.currentThread().getName() +
                            "即将到达集合地点3，当前已有" + (cb.getNumberWaiting() + 1) + "个已经到达，" + (cb.getNumberWaiting() == 2 ? "都到齐了，继续走啊" : "正在等候"));
                    cb.await();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            };
            service.execute(runnable);
        }
        service.shutdown();
    }
}
